Add missing SHELL build-arg

Change-Id: Ic645c0411928f8b69c4d5b21a90462170576e7bc
diff --git a/Cargo.toml b/Cargo.toml
new file mode 100644
index 0000000..e5a3d8e
--- /dev/null
+++ b/Cargo.toml
@@ -0,0 +1,10 @@
+[package]
+name = "atmosphere"
+edition = "2021"
+
+[dev-dependencies]
+rustainers = { path = "crates/rustainers" }
+tokio = { version = "1", features = ["macros", "rt-multi-thread"] }
+
+[workspace]
+members = ["crates/passwd", "crates/rustainers"]